Circuit breaker



Dec. 30, 1930. F. G. VON HOORN CIRCUIT BREAKER Original Fil ed Aug.

11, 1927 2 Sheets-Sheet 1 INSULATION INVENTOR Fred (ivon I"! oor n ATT'ORNEY Dec. 30, 1930.

F. G. VON HOORN CIRCUIT BREAKER 11, 1927 2 Sheets-Sheet 2 Original Filed Aug.

Fig.2.

INSULATION INVYENTOR Fred G. von Hoorn.

ATVTORNEY Patented Dec. 30, 1930 UNITED STATES PATENT OFFICE FRED G. VON HOORN, OF EBIDGEPOBT, CONNECTICUT, ASSIGNOR TO WESTINGHOUSE ELECTRIC dc MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA CIRCUIT BREAKER Application filed August 11, 1927, Serial 110. 212,290. Renewed May 19, 1980.

- overload and short-circuit conditions for opening the circuit and wherein the contact members thereof are held in close relation by a movable carrier or cradle that is retained in set position by a current-responsive device.

Another object of my invention is to provide a circuit breaker having the above noted characteristics wherein means are provided for automatically returning the carrier or cradle to a set position. i

A further object of my invention is to-provide a circuit breaker wherein many of the parts may be stamped from sheet metal and which is relatively inexpensive to manufacture and which may-be readily assembled.

In my copending application Serial No. 212,289, I have described a circuit breaker having means for automatically returning the carriage to set position comprising an over-center spring which serves to actuate the circuit-breaker operatingv mechanism and return the carrier to set position,.the'

spring being connected directlyto the operating means.

It is an ob]ect of my invention to modify the construction of the circuit'breaker shown in the above noted ap lication and to provide an over-center spring that shall-be coni nected indirectly to the operating member for reasons that will hereinafter appear.

. These and other objects that will e made to appear "throughout. the further description of my invention are attained in the circuit-breaker application hereinafter described and illustrated in the accompanying drawings wherein;

7 Figure 1 is .av sectional view of a circuit breaker embodying features of my invention, showing position but with the carrier in set position. Referring to the drawings, the circuit breaker comprises an insulating base 3, that ,is provided with a cover 4 made of sheet material. A terminal member 5 is secured to the base and carries a contact plate 6 which is adapted to be engaged by a contact plate 7, that is secured to a flexible switch arm 8 that is mounted upon a bracket 9 of U-shape.

The bracket 9 is pivoted to a pivot shaft 11 which is supported on a bracket 12 that is attached to the base by means of bolts 13. A

flexible shunt 14 serves to conductively con- ,nect the switch arm 8 to a terminal member 15 through the medium of the bracket 12 to which the shunt 14 is attached.

A bi-metal thermal element 16, of U-shape is connected, at one end, tothe terminal 15 and, at the other end, to a terminal (not shown) to which the line conductor is 'connected. The current, therefore, passes throu h the circuit breaker by firsttrafversing t ebi-metal' element 16 and thence, through terminal 15, bracket 12, shunt 14,

switch arm 8, movable contact plate 7 and contact plate 6, to the terminal 5 which is connected to the line conductor (not shown). The switch arm 8 is actuated through the medium of a toggle comprisin links 17 and V 18 that are pivoted to one anot er by a knee ivot 19. The link 17 is of U-shape, the side Ears therefor being connected by an integral cross bar 21. The link 17 is pivoted to the bracket 9 by means of a pivot shaft 22. The

link 18 is also of U=-sha e, the side plates therefor being connected y an integral cross bar 23. The outer ends-of the link 18 are supported in notches 24 of U-shape provided in the side plates 25 of a carrier or cradle 26.

Thecradle 26 is of U-sha ,e' also, the side plates 25 being connected y integralcross bars 27 and 2 8. The cradle 26 is pivotally mounted upon a shaft 29 that is supported in a bracket 31 which is of U-shape, the side plates thereof being integrally connected by a cross-bar 32 that is secured to the insulatbase 3 by means of bolts 33.

he carrier or cradle 26 is retained in'the set position shown in Fig. 1 b a latch 34.

attached to the free end of the i-metal element 16 and insulated therefrom by insulating washers 35.

As illustrated in Fig. 1, the toggle is in the made position wherein the knee pivot lies slightly above a line connecting the shaft 22 and the apices of the notches 24. It will be understood that the outer ends of the links 18 are forked at 36 to provide a seat which engages the apices of the notches 24.

An operating arm 37 of U-shape, having the side plates thereof connected by an integral cross bar 38, is pivotally mounted on the bracket 31 for rotation about a shaft 39 supported on the bracket. The operating arm 37 is provided with an arcuate slot 41 which serves as a guide and limiting means for limiting the extent of movement of the operating arm 37, the shaft 29 being disposed in the slot 41.

With the exception of the specific construction of the operating arm, the apparatus above described is substantially like that disclosed and more specifically described in my copending application Serial No. 212,289 above referred to.

An over-center spring 42 is connected, at one end, to the knee pivot 19 and, at its outer end, to the operating arm 37. This spring serves to move the knee pivot downward when the operating arm is moved downward manually and thereby causing the toggle to collapse when the knee P1V0|J 19 has moved below a line connecting the shaft 22 and the apices of the notch 24 in the carrier 26. When the toggle collapses, the spring 42 contracts and pulls the switch arm 8 to the open position. At such time, the parts of the apparatus will occupy the positions shown in Fig. 2.

In order to close the circuit breaker manually, the operating arm 38 is returned to the position shown in- Fig. 1. This movement returns the knee pivot 19 to its original position and moves the toggle links to the made position wherein the contact plate 7 is yieldingly retained in conductive engagement with the contact plate 6.

The operating arm 37 is provided with an insIrlat-ing handle 43 which pro'ects through a slot 44 in the cover 4, the ban 1e being provided with extensions 43' for closing the slot 44, regardless of the position of the operating handle.

When an overload or short-circuit condition exists in the circuit, the bi-metal thermal element- 16 is heated by the excessive flow of current and moves the latch 34 downward out of engagement with the shoulder 45 on the carrier 26, thereby releasing it. The spring 42 immediately contracts and rotates the carrier 26 counter-clockwise about the shaft 29,

It is an object of my invention to automatically return the carrier 26 to the set position in order that it shall be engaged by the latch 34 when the bi-metal element returns to its normal position. For this purpose, I have provided a resetting arm 46 that is of U- shape, the side plates thereof being connected by an integral cross bar 47. A resetting spring 48 is pivotally connected, at one end, to the resetting arm 46 by a pin 49, the spring being connected, at the other end, to the shaft 39 about which the operating mm 37 rotates. The operating arm 46 is connected to the operating arm 37 by means ofa pin 51 on the arm 37 that engages a slot 52 in the arm 46, thus providing a lost-motion connection between the arm 46 and the operating arm 37. The spring 48 is of the over-center type and, when in the position shown in Fig. 1, serves to retain the arm 46 in the retracted position shown, the center line of the spring being above the center of the shaft 29 upon which the arm 46 is pivoted. When the carriage 26 is released by the bi-metal element 16, the knee pivot 19 of the toggle is moved to a point below a line connecting the shaft 39 and the outer end of the spring 42 that is attached to the operating arm 37.

The spring 42 then moves the operating arm 37 and handle 43 downward toward the open position. The pin 51, carried by the operating arm 37, engages the lower end of the slot 52 and rotates the arm 46 clockwise, thus moving the pin 49 below a line connecting the shafts 39 and 29. This action permits the spring 48 to contract and move the arm 46 and to continue movement of the arm 46 until the cross bar 47 engages the edge 53 of the carrier 26 which is then moved by the arm 46 to the set position shown in Fig. 2. At this time, the operating arm 37 and the handle 43 will occupy the open position shown in Fig. 2. When the bi-metal element cools sufiiciently to move the latch 37 into engagement with the shoulder 45, the circuit-breaker parts will occupy the positions shown in'Fig. 2. The circuit breaker may then be manually closed by moving the operating handle to the closed position shown in Fig. 1. Should an overload or short-circuit condition prevail, the circuit breaker will immediately open,

regardless of whether the operating handle is being held by the operator or not. The circuit breaker is, therefore, trip-free of the handle.

While I have illustrated but one embodiment of my invention, it will be apparent to those skilled in the art that various changes. modifications, substitutions, additions and omissions may be made in the apparatus illustrated without departing from the spirit and scope of my invention as set forth in the appended claims.

I claim as my invention: 1. The combination with a witch o a t supported in closed position by a. releasable carrier that is retained in set position by a current-responsive element and which auses opening IIIOVGIIlGllt of the switch contact when released, and an operating means for moving the switch contact to open and closed positions while the carrier is in set position,

when released, and an operating means for moving the switch contact to open and closed positions while the carrier is in set position including a pivoted operating member, of means for automatically returning the carrier to set position after it has been released the pivot of the said operating member, an over-center spring attached to the arm for actuating it after it has been moved a predetermined distance and means for automatically moving the operating member when the carrieris released.

In testimony whereof, I: have hereunto subscribed my name this (5th day of July, 1927.

FRED G. voN HOORN.

by the c1irrent-responsive element comprising a member pivoted eccentric to the pivot of the said operating member and an overcenter spring attached to the last said memher for actuating it when it has been moved a predetermined distance by the operating A means.

3. The combination with a switch contact supported in closed position by a releasable carrier that is retained in set position by a current-responsive element and which causes opening movement of the switch contact when released, and an operating means for moving the switch contact to open and closed positions while the carrier is in set position, including a pivoted operating member, of means for automatically returning the carrier to set position, and for moving the operating member to open position after the carrier has been released by the current-responsive element comprising an arm pivoted eccentric to the pivot of the said operating member and an over-center spring attached to the arm for actuating it after it hasbeen moved a predetermined distance.

4 The combination with a switch contact supported in closed position by a releasable carrier that is retained in set position by a current-responsive element and which causes opening movement of the switch contact when released, and an operating means for moving the sw tch contact to open and closed positions while the carrier is in set position, including a pivoted'operating member, of means for automatically returning the carrier to set position, and for moving the operating member to open position after the carrier has been released by the current-responsive element comprising an arm pivoted eccentric to 

